libbacktrace: only build libbacktrace_offline static library.

As device may not have libbacktrace_offline shared library, simpleperf
no longer rely on it. So there is no reason to keep libbacktrace_offline
shared library.

Bug: 28152982
Change-Id: If8e31b1434646dbbfed60264eb25f034bc5d6946
(cherry picked from commit 51e607056dd0db93ef683d05349dd98648c47e47)
diff --git a/libbacktrace/Android.mk b/libbacktrace/Android.mk
index d5a7e06..ee25e08 100644
--- a/libbacktrace/Android.mk
+++ b/libbacktrace/Android.mk
@@ -87,7 +87,7 @@
 	BacktraceOffline.cpp \
 
 # Use shared llvm library on device to save space.
-libbacktrace_offline_shared_libraries := \
+libbacktrace_offline_shared_libraries_target := \
 	libbacktrace \
 	libbase \
 	liblog \
@@ -95,25 +95,20 @@
 	libutils \
 	libLLVM \
 
-libbacktrace_offline_static_libraries := \
+libbacktrace_offline_static_libraries_target := \
 	libziparchive \
 	libz \
 
-module := libbacktrace_offline
-build_type := target
-build_target := SHARED_LIBRARY
-include $(LOCAL_PATH)/Android.build.mk
-
-libbacktrace_offline_shared_libraries := \
-	libbacktrace \
-	libbase \
-	liblog \
-	libunwind \
-	libziparchive-host \
-
 # Use static llvm libraries on host to remove dependency on 32-bit llvm shared library
 # which is not included in the prebuilt.
-libbacktrace_offline_static_libraries := \
+libbacktrace_offline_static_libraries_host := \
+	libbacktrace \
+	libunwind \
+	libziparchive-host \
+	libz \
+	libbase \
+	liblog \
+	libutils \
 	libLLVMObject \
 	libLLVMBitReader \
 	libLLVMMC \
@@ -122,8 +117,11 @@
 	libLLVMSupport \
 
 module := libbacktrace_offline
+build_type := target
+build_target := STATIC_LIBRARY
+libbacktrace_offline_multilib := both
+include $(LOCAL_PATH)/Android.build.mk
 build_type := host
-libbacktrace_multilib := both
 include $(LOCAL_PATH)/Android.build.mk
 
 #-------------------------------------------------------------------------
@@ -170,13 +168,33 @@
 backtrace_test_shared_libraries := \
 	libbacktrace_test \
 	libbacktrace \
-	libbacktrace_offline \
 	libbase \
 	libcutils \
+	liblog \
 	libunwind \
 
 backtrace_test_shared_libraries_target += \
 	libdl \
+	libutils \
+	libLLVM \
+
+backtrace_test_static_libraries := \
+	libbacktrace_offline \
+
+backtrace_test_static_libraries_target := \
+	libziparchive \
+	libz \
+
+backtrace_test_static_libraries_host := \
+	libziparchive-host \
+	libz \
+	libutils \
+	libLLVMObject \
+	libLLVMBitReader \
+	libLLVMMC \
+	libLLVMMCParser \
+	libLLVMCore \
+	libLLVMSupport \
 
 backtrace_test_ldlibs_host += \
 	-ldl \